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Mathew Rosengart, recognized as one of the nation’s preeminent litigators, has been described as a “heavyweight attorney” by Law360, a “powerhouse lawyer” by ABC, and “Hollywood’s King of Litigators” by Variety. Described by his long-time client Sean Penn as a “tough as nails streetfighter with a big brain and bigger principles,” Mathew is a former federal prosecutor, previously serving as a Supervisory Assistant United States Attorney and Justice Department Trial Attorney. A Governor of the Beverly Hills Bar Association, Mathew has been recognized as a California Lawyer Attorney of the Year and one of the Top 100 lawyers in the State by the Daily Journal; a Sports & Entertainment Law Trailblazer by The National Law Journal; Lawyer of the Year by Above the Law; Litigator of the Week by The American Lawyer; Lawyer of the Week by Original Jurisdiction; a Top 100 Lawyer and LA500 Visionary Leader by the Los Angeles Business Journal; a "Litigation Star" by Benchmark Litigation; and a Leader of Influence and Top Litigator & Trial Attorney by the LA Business Journal, which honors “masters of their craft” who “go to the proverbial mat to fight for their clients.” The issue recognized Mathew as “one of the most influential litigators” in Los Angeles and a “go to litigator for Hollywood’s elite and Corporate America” who is “one of the nation’s preeminent litigators.”

Mathew has also been listed in The Best Lawyers in America, been named as a Law360 MVP, which recognizes “the elite slate of attorneys” who “have distinguished themselves from their peers by securing hard-earned successes in high-stakes litigation,” and been lauded as a “heavy-hitting trial lawyer,” “legal powerhouse,” “powerful litigator,” “legal warrior” who is “principled,” and “heavyweight lawyer” by The Legal 500, Yahoo News, Newsweek, The View, Good Morning America, and The Guardian. He has also been recognized by NPR as a lawyer with “a lot of star power,” by Los Angeles Magazine as a “winner” and “heavy hitter” with “a long history of getting results for his big name clients,” and by The Wall Street Journal, The Hollywood Reporter, and NBC’s Today as a “high profile litigator,” a “Hollywood Power Lawyer,” and a “celebrity power attorney.”

Former Supreme Court Justice David Souter, for whom Mathew clerked on the New Hampshire Supreme Court, praised Mathew’s “intelligence,” “instinct,” and “personal integrity,” and his former Justice Department supervisor and now United States District Judge Robert J. Conrad called Mathew “one of the sharpest lawyers I’ve ever met at the Department of Justice,” whose “judgment is impeccable.”

Among many other cases, Mathew won a defamation lawsuit for Sean Penn; a $6 million “cutting rights” case for Academy Award winner Kenneth Lonergan regarding his film “Margaret” starring Matt Damon; a multi-year $20 million arbitration for his client Credit Suisse against billionaire Ronald Lauder and 11 other claimants; and a $14 million trial verdict in a New York trial (on a counterclaim) after extensive bi-coastal litigation for his hedge fund client Sandton Capital against a film production company. Mathew also recently served as lead counsel for Fortune 20 company Verizon in one of the largest False Claims Act cases in the country, involving more than $500 million in claims. 

Mathew has been recognized several times by The American Lawyer in its “Litigator of the Week” column, for going from “defense-to-offense” for NBA superstar Jimmy Butler in a case involving Mathew’s innovative use of the California Talent Agency Act, after obtaining the suspension of Britney Spears’s father as conservator of her Estate, and for obtaining the dismissal at trial of a case brought against one of his clients by the National Labor Relations Board. In addition to complex commercial litigation, Mathew has perennially been recognized as one of the nation’s leading entertainment litigators by both The Hollywood Reporter in its “Power Lawyer Report” (listing the industry’s Top-100 most influential attorneys) and Variety (in its “Legal Impact Report,” spotlighting the world's leading attorneys in the entertainment industry).

Mathew has delivered Boston College Law School’s Dean’s Distinguished Lecture, spoken at Harvard Law School, and was a keynote speaker at the ABA's Forum on the Entertainment and Sports Industries. He is a recipient of Trinity College of Dublin’s Praeses Elit Award, the highest honor bestowed by its Law Society, Variety’s Power of Law Award for legal excellence and philanthropy, and the Beverly Hills Bar Association’s Excellence in Advocacy Award.


  • Litigation
  • Media and entertainment litigation
  • White collar criminal defense



  • Law Clerk to Justice David H. Souter, Supreme Court of New Hampshire
  • Trial Attorney, Civil and Criminal Divisions of the United States Department of Justice 
  • Supervisory Assistant United States Attorney, United States Department of Justice 
  • Senior Associate Independent Counsel/Supervisory Assistant United States Attorney, Office of Independent Counsel 
  • Trial Attorney, United States Department of Justice, Criminal Division Campaign Finance Task Force

Recognition & Leadership

  • Listed, Law360, "Media & Entertainment MVP," 2022 (Recognizing “elite slate of attorneys who have distinguished themselves by securing hard earned successes in high stakes litigation”)
  • Listed, Daily Journal
    • California Lawyer Attorney of the Year, 2022
    • Top 100 Lawyers (listing the Top 100 lawyers in the State)
  • Listed, Los Angeles Business Journal
    • "Top 100 Lawyers List," 2022-2023
    • “Leaders of Influence: Litigators & Trial Attorneys,” 2021-2023 (Recognizing Los Angeles’s Top Litigators and “Masters Of Their Craft”)
    • LA500 List of Visionary Leaders, 2022-2023
  • Listed, The National Law Journal, Sports & Entertainment Law Trailblazer
  • Listed, The American Lawyer, Litigator of the Week and “Shout Out,” Litigator of the Week
  • Listed, Billboard magazine, "Top Music Lawyers," 2022-2023
  • Listed, Variety, "Legal Impact Report," 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023
  • Listed, The Hollywood Reporter, "Power Lawyers: Top 100 Most Influential Entertainment Lawyers in America," 2014, 2015, 20162017, 2021, 2022
  • Listed, The Hollywood Reporter, "Power Lawyers: Hollywood's Top 100 Attorneys List," 2023
  • Listed, The Legal 500 United States, Media and Entertainment: Litigation, "Other Key Lawyer," 2023
  • Lawyer of the Year, Above the Law, 2022
  • Listed, The Best Lawyers in America, Criminal Defense: White Collar, 2023-2024
  • Listed, Benchmark Litigation, "Litigation Star," 2023
  • Shortlisted, Benchmark Litigation, Entertainment Litigator of the Year, 2023
  • Recipient, Variety, Power of Law Award, 2022
  • Recipient, Praeses Elit Award (Trinity College of Dublin, Law Society)
  • Recipient, Beverly Hills Bar Association’s Excellence in Advocacy Award
  • Lawyer of the Week, Judicial Notice/Original Jurisdiction
  • Featured, Los Angeles Confidential Magazine, "Power Player"
  • Special Achievement Award for Meritorious Acts of Service, United States Department of Justice
  • Federal Bar Association’s Younger Lawyer Award – Awarded by Panel of Federal Judges to the Top 5 government litigators under age 36
  • Special Act Awards for Outstanding Performance, United States Department of Justice
  • Commendation, federal prosecution and conviction of defendant in United States v. Sheffield, United States Department of Justice, Bureau of Alcohol Tobacco & Firearms, Internal Affairs
  • Commendation, federal prosecution and conviction of defendant in United States v. Brisbane, United States Department of Justice
  • Board of Governors, Beverly Hills Bar Association, 2020 
  • Keynote Speaker, American Bar Association, Forum on the Entertainment and Sports Industries
  • Dean’s Distinguished Lecture, Boston College Law School
  • Speaker, Harvard Law School, Harvard Ass’n for Law and Business
  • Adjunct Professor of Law, "Criminal Procedure: Grand Jury Law & Practice," Fordham Law School, 2004-2006 
  • Faculty, United States Attorney General's National Advocacy Center, lecturing in Trial Practice, 2000
  • Dean's Advisory Council, Tulane University
  • Member, Association of Business Trial Lawyers Los Angeles


  • J.D., cum laude, Boston College Law School
  • B.A., Tulane University
  • California
  • New York
  • U.S. District Court for the Southern District of New York
  • U.S. District Court for the Eastern District of New York
  • U.S. District Court for the Central District of California